What question did this study set out to answer?

This research aims to investigate the relativistic corrections in the photoproduction of quarkonia using NRQCD.

June 27, 2026Open Access

Relativistic corrections to exclusive photoproduction of Quarkonia near-threshold

Key Points

This research aims to investigate the relativistic corrections in the photoproduction of quarkonia using NRQCD.
Utilized non-relativistic QCD (NRQCD) for calculations.
Examined exclusive photoproduction of vector quarkonia in the near-threshold region.
Analyzed cross-sections for J/ψ and Υ, compared J/ψ results to data.
Relativistic corrections for J/ψ are large, causing breakdown in GPD moment expansion near threshold.
Calculated cross-sections for J/ψ show notable discrepancies from prior data.
Endpoint divergences identified for relativistic corrections away from near-threshold.

Abstract

A bstract Non-relativistic QCD (NRQCD) is used to calculate the relativistic correction to the amplitude for exclusive photoproduction of vector Quarkonia in the near-threshold region within the generalized parton distribution (GPD) framework. The relativistic corrections are found to be large for J / ψ , and lead to a breakdown of the GPD moment expansion near threshold. Cross-sections for both J / ψ and Υ are calculated with the former being compared to the data. We also demonstrate the presence of endpoint divergences for the relativistic correction away from the near-threshold regime.

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